Compilare: user.cpp: In function ‘int main()’: user.cpp:26:9: warning: unused variable ‘last’ [-Wunused-variable] int last=0; ^ user.cpp:27:9: warning: unused variable ‘first’ [-Wunused-variable] int first=-1; ^ user.cpp:28:9: warning: unused variable ‘let’ [-Wunused-variable] int let=0; ^ user.cpp:29:9: warning: unused variable ‘st’ [-Wunused-variable] int st=0; ^ user.cpp:16:31: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d%d", &n, &m1); ^